Sucking salamander uses jaw power to bend prey

Giant salamanders can handle prey larger than their mouths. As shown in this video, the amphibian can make a long roach bend into its open jaws by the power of suction alone.

Egon Heiss from the University of Antwerp, Balgium, and colleagues captured the clip to better understand the mechanism, of which little is known. Compared with fish - which suck up prey by drawing in water that's later expelled through their gills - salamanders release water back through their mouths again.

A fluid dynamics model, shown in the second part of the video, uses CT scans and high-speed videos to mimic the action. "It proves that only the fast separation of the jaws generates the high fluid velocities, as no other movements of the salamander were simulated," says Heiss. After the initial jaw opening, a bony structure at the back of the mouth, which in fish is responsible for sucking, also moves, but the model shows that this motion isn't involved in prey capture. Instead, it seems to maintain flow.

The team thinks that the changeover to jaw-powered suction could have been important in the evolution of terrestrial life. "This could have opened the path for further modifications, such as the evolution of a fleshy tongue, without losing performance as aquatic predators," write the team.